Blood circulation system

ABSTRACT

Disclosed is an artificial heart and lung apparatus ( 100 ) that can be connected to a patient (P), and transfers removed blood to a human body via a roller pump ( 120 ), the system including: the roller pump ( 120 ); a blood removal line ( 101 ) which transfers removed blood to the roller pump ( 120 ); a first blood transfer line ( 104 ) that transfers blood, which is transferred from the roller pump ( 120 ), to the human body; a blood removal rate sensor ( 111 ) that is provided in the blood removal line ( 101 ); and a control unit ( 140 ), in which the control unit ( 140 ) performs control such that a blood transfer rate of the roller pump ( 120 ) is in a specific range with respect to a blood removal rate measured by a blood removal rate sensor ( 111 ).

TECHNICAL FIELD

The present invention relates to a blood circulation system thatcirculates removed blood via a blood transfer pump. This application isa Continuation of U.S. patent application Ser. No. 15/502,949, filedFeb. 9, 2017, which is a U.S. National Stage entry of PCT ApplicationNo. PCT/JP2015/073428, filed Aug. 20, 2015, which claims priority toJapanese Patent Application No. 2014-167559, filed Aug. 20, 2014, andJapanese Patent Application No. 2015-53600, filed Mar. 17, 2015, thecontents of which are incorporated herein by reference.

BACKGROUND ART

In the related art, an artificial heart and lung and a blood circulationsystem for adjunctively circulating blood are widely used as necessarywhen a heart is stopped or is approximately stopped during or after asurgery such as cardiac surgery.

As shown in FIG. 9, an artificial heart and lung apparatus (bloodcirculation system) 500 equipped with an artificial heart and lung inthe related art includes a blood removal line 501; a reservoir 502; ablood line 503; a blood transfer line 504; a first blood transfer line505; an artificial lung 506; and a second blood transfer line 507.

The blood removal line 501 transfers blood, which has been received froma vein of a patient (human body) P, to the reservoir 502. The bloodremoval line 501 is a tube formed of resin such as polyvinyl chloride.

The reservoir 502 includes a tank therein, and temporarily stores thetransferred blood.

The blood transfer pump 504 transfers the blood stored in the reservoir502 to the artificial lung 506 via the blood line 503 through which thereservoir 502 is connected to the blood transfer pump 504, and via thefirst blood transfer line 505 through which the blood transfer pump 504is connected to the artificial lung 506. For example, a roller pump or acentrifugal pump is used as the blood transfer pump 504. The bloodtransfer pump 504 is controlled by a signal output from a blood transferpump control unit 540.

The artificial lung 506 includes a hollow fiber membrane, a flatmembrane, or the like having good gas permeability, and has the functionof discharging carbon dioxide from and adding oxygen to blood.

The second blood transfer line 507 receives the blood, from which carbondioxide has been discharged and to which oxygen has been added by theartificial lung 506, and transfers the blood to an artery of the patientP.

Advanced knowledge and techniques are required to operate the artificialheart and lung apparatus 500 with such a configuration. Typically, aclinical engineer adjusts a blood flow rate via a manual operationaccording to a doctor's instructions.

When adjusting the blood flow rate via a manual operation, the clinicalengineer is required to adjust a blood flow rate in the blood removalline 501 by pinching the blood removal line 501 with a forceps whileconfirming the degree of removal of blood or an arterial pressure of thepatient.

Since the clinical engineer adjusts the amount of discharge of the bloodtransfer pump by manually controlling the rotational speed of the bloodtransfer pump (roller pump or centrifugal pump) when adjusting the bloodflow rate, a complex and advanced operation technique is required inaddition to the adjustment of each line.

Patent Document 1 discloses technology to adjust a blood removal rate inwhich the blood removal line 501 is pinched and deformed to accuratelyand simply adjust the blood removal rate via an artificial heart andlung apparatus.

In order to adjust the flow rate of blood to be removed via the bloodremoval line 501, the artificial heart and lung apparatus disclosed inPatent Document 1 pinches and deforms the blood removal line 501 byoperating a blood removal regulator 521, which includes a clamper formedof a pair of clamp members and a servo motor, via a blood removalregulator operation unit 520.

Patent Document 2 discloses technology in which a blood removalregulator control unit is interlocked with a blood transfer regulatorcontrol unit, a blood removal rate and a blood transfer rate aresimultaneously controlled via operation of one of the control units, andthus a blood flow rate of an artificial heart and lung apparatus isefficiently adjusted.

CITATION LIST Patent Document

[Patent Document 1] Japanese Unexamined Patent Application, FirstPublication No. 62-027966

[Patent Document 2] Japanese Unexamined Patent Application, FirstPublication No. 2006-020712

SUMMARY OF INVENTION Technical Problem

The amount of blood to be removed may change depending on surgicalsituations, and it may be difficult to promptly and stably transfer anamount of blood corresponding to a blood removal rate in a case wherethe blood removal rate changes significantly.

A blood circulation system which circulates removed blood via a bloodtransfer pump requires technology by which blood is stably circulated ata suitable flow rate.

The present invention is made in light of this problem, and an object ofthe present invention is to provide a blood circulation system that iscapable of stably circulating removed blood at a suitable flow rate viaa blood transfer pump.

Solution to Problem

In order to solve this problem, the present invention proposes thefollowing means.

According to a first aspect of the present invention, there is provideda blood circulation system that can be connected to a human body, andtransfers removed blood to the human body via a blood transfer pump, thesystem including: the blood transfer pump; a blood removal line throughwhich removed blood flows to the blood transfer pump; a blood transferline that transfers blood, which is sent from the blood transfer pump,to the human body; blood removal rate measurement means that is providedin the blood removal line; and a control unit, in which, according to ablood removal rate parameter measured by the blood removal ratemeasurement means, the control unit controls a blood transfer rate ofthe blood transfer pump such that the transfer rate of blood flowingthrough the blood transfer line is in a specific range with respect tothe removal rate of blood flowing through the blood removal line.

In the blood circulation system of the invention, according to the bloodremoval rate parameter measured by the blood removal rate measurementmeans, the control unit controls the blood transfer rate of the bloodtransfer pump such that the transfer rate of blood flowing through theblood transfer line is in a specific range with respect to the removalrate of blood flowing through the blood removal line. Therefore, it ispossible to ensure that the blood transfer rate is in the specific rangewith respect to the blood removal rate.

As a result, even if the blood removal rate changes, it is possible totransfer an amount of blood to the human body at a blood removal rate ina specific range, and it is possible to stably circulate blood at asuitable flow rate.

In the present invention, the blood removal line represents a blood lineamong blood lines of the blood circulation system which is formed suchthat blood removed from the human body flows through the blood linetoward the blood transfer pump. More specifically, the blood removalline represents a blood line leading toward a reservoir. The bloodtransfer line represents a blood line leading toward the human body fromthe blood transfer pump.

In a blood circulation path, a blood line, which is positioned on thedownstream side of a portion (for example, reservoir) in which bloodopens to a space and in which there is no normal continuity of a bloodflow rate, may not represent the blood removal line or the bloodtransfer line.

For the sake of convenience, a blood line may indicate a portion of theblood removal line and the blood transfer line.

In the present invention, the specific range with respect to the bloodremoval rate implies that the blood transfer rate is in a range which isset with respect to the blood removal rate. The amount of deviation ofthe blood transfer rate with respect to the blood removal rate isrepresented by a difference in flow rate (for example, an upper limit orlower limit difference in flow rate) with respect to the blood removalrate.

In the present invention, needless to say, the blood removal ratemeasurement means includes measurement means for measuring a bloodremoval rate, and includes measurement means for measuring various bloodremoval rate parameters for specifying a blood removal rate.

Needless to say, the blood removal rate parameters include a bloodremoval rate, and are parameters which change corresponding to a bloodremoval rate. That is, the blood removal rate parameters include variousparameters for specifying a blood removal rate, for example, the flowspeed of removed blood in a case where a cross-sectional flow path areaof the blood removal line is already known, and a parameter (forexample, a change in ultrasonic wave frequency) for specifying the flowspeed.

In the present invention, in a case where according to the blood removalrate parameter, control is performed such that the blood transfer rateis in a specific range with respect to the blood removal rate, the bloodremoval rate may not be calculated and the blood transfer pump may bedirectly controlled according to a measured value of the blood removalrate parameter.

According to a second aspect of the present invention, in the firstaspect, according to the blood removal rate parameter measured by theblood removal rate measurement means, the control unit controls theblood transfer rate of the blood transfer pump such that the transferrate of blood flowing through the blood transfer line is synchronizedwith the removal rate of blood flowing through the blood removal line.

In the blood circulation system of the invention, according to the bloodremoval rate parameter measured by the blood removal rate measurementmeans, the control unit controls the blood transfer rate of the bloodtransfer pump such that the transfer rate of blood flowing through theblood transfer line is synchronized with the removal rate of bloodflowing through the blood removal line. Therefore, it is possible totransfer the same amount of blood as the amount of removed blood to thehuman body.

As a result, even if the blood removal rate changes, it is possible totransfer the same amount of blood as the amount of removed blood to thehuman body, and it is possible to stably circulate blood at a suitableflow rate.

In the present invention, the synchronization of the transfer rate ofblood flowing through the blood transfer line with the removal rate ofblood flowing through the blood removal line implies that the bloodtransfer rate of the blood transfer pump is controlled to be the same asthe blood removal rate. That is, errors caused by a time lag of acontrol signal output to the blood transfer pump or a response time ofthe blood transfer pump are allowed.

The synchronization includes not only a case in which the blood removalrate exactly coincides with the blood transfer rate, but also a case inwhich the blood removal rate substantially coincides with the bloodtransfer rate.

The synchronization includes a case in which the same amount of blood asthe amount of removed blood is transferred by the blood transfer pumpwhile the transferring of blood is delayed by an amount of time set inadvance.

According to a third aspect of the present invention, the first andsecond aspects further include a correction process setting unit, inwhich, according to correction process data input to the correctionprocess setting unit, the control unit performs correction such that theblood transfer rate of the blood transfer pump corresponds to the bloodremoval rate.

In the blood circulation system of the invention, the correction processsetting unit is provided, and according to the correction process datainput to the correction process setting unit, the control unit performscorrection such that the blood transfer rate of the blood transfer pumpcorresponds to the blood removal rate. In a case where a combination ofthe blood removal rate measurement means and the blood transfer pump ischanged, and the blood transfer rate of the blood transfer pumpcontrolled by the blood removal rate parameter does not correspond tothe blood removal rate due to individual variations of the blood removalrate measurement means and the blood transfer pump, the blood transferrate can be efficiently corrected to correspond to the blood removalrate.

According to a fourth aspect of the present invention, the first tothird aspects further include a roller pump that is the blood transferpump, in which the control unit controls the rotational speed of theroller pump according to the blood removal rate parameter measured bythe blood removal rate measurement means.

In the blood circulation system of the invention, the roller pump isincluded as the blood transfer pump, and the control unit controls therotational speed of the roller pump according to the blood removal rateparameter measured by the blood removal rate measurement means. As aresult, the blood circulation system is prevented from being affected bypressure, and it is possible to ensure a stable blood transfer rate bycontrolling the rotational speed.

According to a fifth aspect of the present invention, the first to thirdaspects further include blood transfer rate measurement means that isprovided in the blood transfer line, in which the control unit controlsthe blood transfer pump by comparison of a blood transfer rate parametermeasured by the blood transfer rate measurement means with the bloodremoval rate parameter measured by the blood removal rate measurementmeans.

In the blood circulation system of the invention, the blood transferrate measurement means is provided in the blood transfer line, and thecontrol unit controls the blood transfer pump by comparison of the bloodtransfer rate parameter measured by the blood transfer rate measurementmeans with the blood removal rate parameter measured by the bloodremoval rate measurement means. Therefore, it is possible to efficientlyreduce the difference between the blood transfer rate and the bloodremoval rate.

As a result, it is possible to efficiently make the blood transfer ratecorrespond to the blood removal rate, and it is possible to performstable blood circulation.

In the present invention, needless to say, the blood transfer ratemeasurement means includes measurement means for measuring a bloodtransfer rate, and includes measurement means for measuring variousblood transfer rate parameters for specifying a blood transfer rate.

Needless to say, the blood transfer rate parameters include a bloodtransfer rate, and are parameters which change corresponding to a bloodtransfer rate. That is, the blood transfer rate parameters includevarious parameters for specifying a blood removal rate, for example, theflow speed of transferred blood in a case where a cross-sectional flowpath area of the blood transfer line is already known, and a parameter(for example, a change in ultrasonic wave frequency) for specifying theflow speed.

A comparison between a blood transfer rate parameter and a blood removalrate parameter implies any one of a comparison therebetween in a casewhere the types of the blood transfer rate parameter and the bloodremoval rate parameter are the same, a direct comparison therebetween ina case where the types of the blood transfer rate parameter and theblood removal rate parameter are different from each other, and acomparison therebetween after one or both of the blood transfer rateparameter and the blood removal rate parameter are converted into formsin which both can be compared to each other.

According to a sixth aspect of the present invention, the fifth aspectfurther includes a centrifugal pump that is the blood transfer pump, inwhich the control unit controls the rotational speed of the centrifugalpump.

In the blood circulation system of the invention, the centrifugal pumpis included as the blood transfer pump, and the control unit controlsthe rotational speed of the centrifugal pump by comparison of the bloodtransfer rate parameter measured by the blood transfer rate measurementmeans with the blood removal rate parameter measured by the bloodremoval rate measurement means. As a result, it is possible to promptlyand stably transfer blood, the transfer rate of which corresponds to ablood removal rate.

According to a seventh aspect of the present invention, in the first tosixth aspects, flow rate adjustment means is provided in the bloodremoval line.

In the blood circulation system of the invention, the flow rateadjustment means is provided in the blood removal line, and thus, it ispossible to efficiently adjust the blood removal rate.

According to an eighth aspect of the present invention, in the first tothird, fifth and sixth aspects, flow rate adjustment means is providedin both the blood removal line and the blood transfer line.

In the blood circulation system of the invention, the flow rateadjustment means is provided in both the blood removal line and theblood transfer line, and thus, it is possible to efficiently adjust ablood flow rate. If the blood transfer pump is a centrifugal pump, it ispossible to prevent the back flowing of blood when the centrifugal pumpstops.

Advantageous Effects of Invention

The blood circulation system of the invention is capable of transferringblood such that the blood transfer rate of the blood transfer pumpcorresponds to the blood removal rate.

As a result, even if the blood removal rate changes, it is possible tostably circulate blood at a suitable flow rate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram showing a schematic configuration of anartificial heart and lung apparatus of a first embodiment of the presentinvention.

FIG. 2 is a block diagram showing a schematic configuration of a controlunit of the artificial heart and lung apparatus of the first embodimentof the present invention.

FIG. 3 is a flowchart showing an operational sequence of the controlunit in a case where a correction process is not performed in theartificial heart and lung apparatus of the first embodiment of thepresent invention.

FIG. 4 is a flowchart showing an operational sequence of the controlunit in a case where a correction process is performed in the artificialheart and lung apparatus of the first embodiment of the presentinvention.

FIG. 5 is a circuit diagram showing a schematic configuration of anartificial heart and lung apparatus of a second embodiment of thepresent invention.

FIG. 6 is a block diagram showing a schematic configuration of a controlunit of the artificial heart and lung apparatus of the second embodimentof the present invention.

FIG. 7 is a flowchart showing an operational sequence of the controlunit in a case where a correction process is not performed in theartificial heart and lung apparatus of the second embodiment of thepresent invention.

FIG. 8 is a flowchart showing an operational sequence of the controlunit in a case where a correction process is performed in the artificialheart and lung apparatus of the second embodiment of the presentinvention.

FIG. 9 is a circuit diagram showing a schematic configuration of anartificial heart and lung apparatus in the related art.

DESCRIPTION OF EMBODIMENTS First Embodiment

Hereinafter, an artificial heart and lung apparatus (blood circulationsystem) of a first embodiment of the present invention will be describedwith reference to FIGS. 1 to 3.

FIG. 1 is a circuit diagram showing a schematic configuration of theartificial heart and lung apparatus of the first embodiment of thepresent invention. Reference sign 100 represents an artificial heart andlung apparatus, reference sign 111 represents a blood removal ratesensor, reference sign 120 represents a roller pump, reference sign 140represents a control unit, and reference sign 160 represents acorrection process setting unit.

As shown in FIG. 1, the artificial heart and lung apparatus 100 includesa blood removal line 101; a reservoir 102; a blood line 103; a firstblood transfer line (blood transfer line) 104; an artificial lung 105; asecond blood transfer line (blood transfer line) 106; a blood removalrate sensor (blood removal rate measurement means) 111; a roller pump(blood transfer pump) 120; a blood removal regulator (flow rateadjustment means) 121; a control unit 140; and a correction processsetting unit 160.

The blood removal line 101, the reservoir 102, the blood line 103, theroller pump 120, the first blood transfer line 104, the artificial lung105, and the second blood transfer line 106 are connected together inthe listed sequence. The blood removal regulator 121 and the bloodremoval rate sensor 111 are disposed in the blood removal line 101 inthe listed sequence.

Blood to be removed via the blood removal line 101 is circulated to apatient (human body) P via the first blood transfer line 104 and thesecond blood transfer line 106.

The blood removal line 101 is a tube formed of resin such as polyvinylchloride. One end of the blood removal line 101 can be connected to thepatient P, and transfers blood, which has been received from a vein, tothe reservoir 102.

A sensor or the like (not shown) is provided in the blood removal line101 so as to monitor the concentration of blood or the concentration ofoxygen as necessary. The sensor or the like may be provided in the bloodline 103 or the first blood transfer line 104 instead of the bloodremoval line 101.

The reservoir 102 includes a tank therein, and temporarily stores thetransferred blood.

A suction line (not shown) is connected to the reservoir 102 so as tosuction blood in a surgical site of the patient P, and a vent line (notshown) is connected to the reservoir 102 so as to suction blood in aright cardiac chamber.

The blood line 103 has the same configuration as that of the bloodremoval line 101. The upstream side of the blood line 103 is connectedto the reservoir 102, and the downstream side of the blood line 103 isconnected to the roller pump 120. The blood line 103 transfers theblood, which has been received from the reservoir 102, to the rollerpump 120.

The roller pump 120 includes a rotating roller and a tube that isdisposed on the outside of the rotating roller and is formed of flexibleresin. If the rotating roller rotates and wipes the tube, and blood issuctioned and transferred out, the blood stored in the reservoir 102 issuctioned via the blood line 103, and is transferred to the artificiallung 105 via the first blood transfer line 104.

The rotational speed of the rotating roller is controlled by a rotationcontrol signal output from the control unit 140, and the roller pump 120suctions and transfers the amount of blood corresponding to therotational speed of the rotating roller.

The first blood transfer line 104 has the same configuration as that ofthe blood removal line 101. The upstream side of the first bloodtransfer line 104 is connected to the roller pump 120, and thedownstream side of the first blood transfer line 104 is connected to theartificial lung 105. The first blood transfer line 104 transfers theblood, which has been transferred out from the roller pump 120, to theartificial lung 105.

The artificial lung 105 includes a hollow fiber membrane, a flatmembrane, or the like having good gas permeability, and dischargescarbon dioxide from and adds oxygen to blood.

A heat exchanger is formed integrally with the artificial lung 105 so asto adjust the temperature of blood.

The second blood transfer line 106 has the same configuration as that ofthe blood removal line 101, and receives the blood, from which carbondioxide has been discharged and to which oxygen has been added, from theartificial lung 105, and transfers the blood to an artery of the patientP.

A filter (not shown) is provided in the second blood transfer line 106so as to remove foreign matter such as thrombi and bubbles from blood.

The blood removal regulator 121 is provided in the blood removal line101. The blood removal regulator 121 includes a clamper 121A formed of apair of clamp members; a servo motor (not shown) that operates theclamper 121A; and a blood removal regulator operation unit 121B. Anoperator changes the cross-sectional area of the blood removal line 101by adjusting the amount of clamp (the amount of pinch) of the clamper121A via the servo motor driven by manually operating the blood removalregulator operation unit 121B, and as a result, the removal rate ofblood flowing through the blood removal line 101 is adjusted.

The blood removal rate sensor (blood removal rate measurement means) 111is provided in the blood removal line 101. The blood removal rate sensor111 transmits a blood removal rate parameter signal, which is measuredusing an ultrasonic sensor that measures the flow speed of blood viaultrasonic waves, to the control unit 140.

Hereinafter, a schematic configuration of the control unit 140 will bedescribed with reference to FIG. 2. FIG. 2 is a block diagram showingthe schematic configuration of the control unit 140 of the firstembodiment.

The control unit 140 includes a blood removal rate parameter signalreceiving unit 141; a blood removal rate calculation unit 142; a rollerpump control amount calculation unit 143; a roller pump control unit144; and a correction process data receiving unit 151.

The control unit 140 is connected to the blood removal rate sensor 111,and the correction process setting unit 160, and the roller pump 120 viacables.

The correction process setting unit 160 is capable of setting correctionprocess data for correcting measurement errors of the blood removal ratesensor 111, variations of a blood transfer rate characteristic(relationship between the rotational speed and the blood transfer rate)of the roller pump 120 or a deviation of the blood transfer rate withrespect to the rotational speed of the roller pump 120 which occurs dueto the combination of the blood removal rate sensor 111 and the rollerpump 120, or correcting a temporary increase of the blood transfer ratewith respect to the blood removal rate.

The correction process data is preferably defined by the amount ofdeviation (the amount of offset, a ratio, or the like) of the bloodtransfer rate with respect to the blood removal rate. Alternatively, thecorrection process data may be defined by other techniques if thecorrection process data is capable of setting the blood transfer rate ofthe roller pump 120 to be in a specific range with respect to the bloodremoval rate.

In the embodiment, the correction process setting unit 160 outputs acorrection process execution instruction indicating the execution of acorrection process.

In the embodiment, the correction process data is preferably setaccording to at least one of the measurement errors of the blood removalrate sensor 111, and the amount of a deviation between the bloodtransfer rate characteristic (relationship between the rotational speedand the blood transfer rate) of the roller pump 120 and a basic bloodtransfer rate characteristic of the roller pump 120, all of which areconfirmed in advance.

The correction process data may be set according to an increase ordecrease in the level of blood in the reservoir 102 which occurs afterblood circulation starts.

The blood removal rate parameter signal receiving unit 141 is connectedto the blood removal rate sensor 111, and receives a blood removal rateparameter signal sent from the blood removal rate sensor 111.

The blood removal rate calculation unit 142 calculates the amount ofremoved blood according to a signal sent from the blood removal rateparameter signal receiving unit 141. Specifically, it is possible tocalculate a blood removal rate by multiplying a blood removal speed(flow rate parameter), which is calculated from the blood removal rateparameter signal, by a flow path area of the blood removal line 101.

The correction process data receiving unit 151 receives the correctionprocess data and the correction process execution instruction, whichhave been set by the correction process setting unit 160, from thecorrection process setting unit 160.

The roller pump control amount calculation unit 143 calculates arotational speed (according to a basic blood transfer ratecharacteristic), which is required to synchronize the blood transferrate of the roller pump 120 with the blood removal rate, according tothe blood removal rate received from the blood removal rate calculationunit 142. It is possible to calculate the rotational speed according tothe basic blood transfer rate characteristic via a data tablerepresenting the relationship between the rotational speed of the rollerpump 120 and the blood transfer rate, or a calculation expressionrepresenting the relationship between the rotational speed of the rollerpump 120 and the blood transfer rate.

The rotational speed to be output to the roller pump 120 is calculatedaccording to the rotational speed according to the basic blood transferrate characteristic and the correction process data received from thecorrection process data receiving unit 151.

The synchronization of the blood transfer rate of the roller pump 120with the blood removal rate is one aspect in which the blood transferrate is controlled to be in a specific range (for example, in a rangerepresented by a ratio to the blood removal rate, or in a rangerepresented by a difference in flow rate with respect to the bloodremoval rate) with respect to the blood removal rate.

The roller pump control unit 144 outputs a signal, which corresponds toa control amount (corrected rotational speed) received from the rollerpump control amount calculation unit 143, to the roller pump 120.

Hereinafter, an operational sequence in a case where the control unit140 of the artificial heart and lung apparatus 100 of the firstembodiment does not perform a correction process will be described withreference to FIG. 3. FIG. 3 is a flowchart showing the operationalsequence of the control unit 140 in a case where a correction process isnot performed in the artificial heart and lung apparatus 100.

(1) First, the control unit 140 receives a blood removal rate parametersignal (S11).

(2) Subsequently, the control unit 140 calculates a blood removal rateaccording to the received blood removal rate parameter signal (S12).

(3) Subsequently, the control unit 140 calculates a control amount(rotational speed) according to a basic blood transfer ratecharacteristic of the roller pump 120 according to the received bloodremoval rate (S13).

(4) Subsequently, the control unit 140 outputs a signal, whichcorresponds to the control amount, to the roller pump 120 (S14).

If S14 is executed, the process proceeds to S11.

S11 to S14 are repeatedly executed at predetermined intervals until asurgery is complete and blood circulation ends.

Hereinafter, an operational sequence in a case where the control unit140 of the artificial heart and lung apparatus 100 of the firstembodiment performs a correction process will be described withreference to FIG. 4. FIG. 4 is a flowchart showing the operationalsequence of the control unit 140 in a case where a correction process isperformed in the artificial heart and lung apparatus 100.

(1) First, the control unit 140 receives a blood removal rate parametersignal (S21).

(2) Subsequently, the control unit 140 calculates a blood removal rateaccording to the received blood removal rate parameter signal (S22).

(3) Subsequently, the control unit 140 calculates a rotational speedaccording to on the basic blood transfer rate characteristic of theroller pump 120 according to the received blood removal rate (S23).

(4) Subsequently, the control unit 140 receives correction process data(S24).

(5) Subsequently, the control unit 140 corrects the rotational speed,which has been calculated in S23 according to the basic blood transferrate characteristic of the roller pump 120, according to the correctionprocess data, and calculates a control amount (corrected rotationalspeed) to be output to the roller pump 120 (S25).

(6) Subsequently, the control unit 140 outputs a signal, whichcorresponds to the control amount (corrected rotational speed), to theroller pump 120 (S26).

If S26 is executed, the process proceeds to S21.

S21 to S26 are repeatedly executed at predetermined intervals until asurgery is complete and blood circulation ends.

In the artificial heart and lung apparatus 100 of the first embodiment,the control unit 140 controls the roller pump 120 such that the bloodtransfer rate of the roller pump 120 is synchronized with the flow rateof removed blood flowing through the blood removal line 101.Accordingly, the amount of blood corresponding to the amount of removedblood can be transferred to the patient P via the first blood transferline 104, the artificial lung 105, and the second blood transfer line106.

As a result, even if the blood removal rate changes, it is possible tostably circulate blood at a suitable flow rate.

In the artificial heart and lung apparatus 100 of the first embodiment,the correction process setting unit 160 is provided, and the controlunit 140 corrects deviations between a measurement characteristic of theblood removal rate sensor 111 and the blood transfer rate characteristicof the roller pump 120 according to correction process data input to thecorrection process setting unit 160. Accordingly, the artificial heartand lung apparatus 100 of the first embodiment is capable of efficientlysynchronizing the blood transfer rate of the roller pump 120 with theblood removal rate.

Since the artificial heart and lung apparatus 100 of the firstembodiment includes the roller pump 120 as the blood transfer pump, theartificial heart and lung apparatus 100 is unlikely to be affected bypressure, and is capable of transferring blood at a stable bloodtransfer rate.

In the artificial heart and lung apparatus 100 of the first embodiment,the blood removal regulator 121 is provided in the blood removal line101, and thus, the flow rate of blood removed via the blood removal line101 is suitably adjusted.

The artificial heart and lung apparatus 100 of the first embodimentincludes the reservoir 102. The artificial heart and lung apparatus 100is capable of synchronizing a blood transfer rate with a blood removalrate or adjusting the blood transfer rate to be in a specific range withrespect to the blood removal rate, and the occurrence of excessivenegative pressure is prevented. Accordingly, an auxiliary circulationapparatus (blood circulation system) in which the reservoir 102 is notprovided and the roller pump 120 is adopted may be used as theartificial heart and lung apparatus 100 shown in FIG. 1.

Second Embodiment

Hereinafter, an artificial heart and lung apparatus (blood circulationsystem) of a second embodiment of the present invention will bedescribed with reference to FIGS. 5 to 8.

FIG. 5 is a circuit diagram showing a schematic configuration of theartificial heart and lung apparatus of the second embodiment of thepresent invention. Reference sign 200 represents an artificial heart andlung apparatus, reference sign 112 represents a blood transfer ratesensor (blood transfer rate measurement means), reference sign 220represents a centrifugal pump (blood transfer pump), reference sign 260represents a correction process setting unit, and reference sign 240represents a control unit.

As shown in FIG. 5, an artificial heart and lung apparatus 200 includesthe blood removal line 101; the reservoir 102; the blood line 103; acentrifugal pump 220; the first blood transfer line (blood transferline) 104; the artificial lung 105; the second blood transfer line(blood transfer line) 106; the blood removal rate sensor 111; a bloodtransfer rate sensor 112; the blood removal regulator (flow rateadjustment means) 121; a blood transfer regulator 122; a control unit240; and a correction process setting unit 260.

The blood removal line 101, the reservoir 102, the blood line 103, thecentrifugal pump 220, the first blood transfer line 104, the artificiallung 105, and the second blood transfer line 106 are connected togetherin the listed sequence. The blood removal regulator 121 and the bloodremoval rate sensor 111 are disposed in the blood removal line 101 inthe listed sequence. The blood transfer regulator 122 and the bloodtransfer rate sensor 112 are disposed in the first blood transfer line104 in the listed sequence.

The blood removal line 101, the reservoir 102, the blood line 103, thefirst blood transfer line 104, the artificial lung 105, the second bloodtransfer line 106, the blood removal rate sensor 111, and the bloodremoval regulator 121 are the same as those of the first embodiment, andthus, a description thereof will be omitted.

Similar to the blood removal rate sensor 111, an ultrasonic sensor isused as the blood transfer rate sensor (blood transfer rate measurementmeans) 112. The blood transfer rate sensor 112 sends a measurementresult to the control unit 240.

The centrifugal pump 220 suctions blood stored in the reservoir 102 viathe blood line 103, and transfers the blood to the artificial lung 105via the first blood transfer line 104 by rotating impeller blades via anAC servo motor or a DC servo motor.

The rotational speed of the centrifugal pump 220 is feedback controlledsuch that a blood transfer rate measured by the blood transfer ratesensor 112 is synchronized with a blood removal rate measured by theblood removal rate sensor 111.

The blood transfer regulator 122 is provided in the first blood transferline 104. The blood transfer regulator 122 includes a clamper 122Aformed of a pair of clamp members; a servo motor (not shown) thatoperates the clamper 122A; and a blood transfer regulator operation unit122B. An operator blocks the first blood transfer line 104 by adjustingthe amount of clamp (the amount of pinch) of the clamper 122A via theservo motor driven by manually operating the blood transfer regulatoroperation unit 122B, and thus, the back flowing of blood when thecentrifugal pump 220 stops is prevented.

Hereinafter, a schematic configuration of the control unit 240 will bedescribed with reference to FIG. 6. FIG. 6 is a block diagram showingthe schematic configuration of the control unit 240 of the secondembodiment.

The control unit 240 includes the blood removal rate parameter signalreceiving unit 141; the blood removal rate calculation unit 142; acentrifugal pump control amount calculation unit 243; a centrifugal pumpcontrol unit 244; a blood transfer rate parameter signal receiving unit245; a blood transfer rate calculation unit 246; and the correctionprocess data receiving unit 151.

The control unit 240 is connected to the blood removal rate sensor 111,the blood transfer rate sensor 112, the correction process setting unit260, and the centrifugal pump 220 via cables.

The blood removal rate parameter signal receiving unit 141, the bloodremoval rate calculation unit 142, and the correction process datareceiving unit 151 are the same as those of the first embodiment, andthus, a description thereof will be omitted.

Since the centrifugal pump 220 of the second embodiment is feedbackcontrolled, there is a low need to take into consideration bloodtransfer rate errors which are caused by a blood transfer ratecharacteristic. In contrast, the blood removal rate sensor 111 and theblood transfer rate sensor 112 have different measurementcharacteristics. If the measurement characteristics (measurement errors)of the blood removal rate sensor 111 and the blood transfer rate sensor112 are different from each other, a deviation between a blood transferrate and a blood removal rate may occur due to the combination of theblood removal rate sensor 111 and the blood transfer rate sensor 112.The deviation between the blood transfer rate and the blood removal rateoccurring due to the combination of the blood removal rate sensor 111and the blood transfer rate sensor 112 is preferably corrected.

The correction process setting unit 260 sets correction process data forcorrecting a deviation occurring due to the combination of the bloodremoval rate sensor 111 and the blood transfer rate sensor 112, orcorrecting a temporary increase of the blood transfer rate with respectto the blood removal rate.

The correction process data is preferably defined by the amount ofdeviation (the amount of offset, a ratio, or the like) of the bloodtransfer rate with respect to the blood removal rate. Alternatively, thecorrection process data may be defined by other techniques if thecorrection process data is capable of setting the blood transfer rate ofthe centrifugal pump 220 to be in a specific range with respect to theblood removal rate. In the embodiment, the correction process settingunit 260 outputs a correction process execution instruction indicatingthe execution of a correction process.

In the embodiment, the correction process data is preferably setaccording to the amount of a deviation between the measurementcharacteristic of the blood removal rate sensor 111 and the measurementcharacteristic of the blood transfer rate sensor 112 which have beenconfirmed in advance.

The correction process data may be set according to an increase ordecrease in the level of blood in the reservoir 102 which occurs afterblood circulation starts.

The blood transfer rate parameter signal receiving unit 245 is connectedto the blood transfer rate sensor 112, and receives a blood transferrate parameter signal sent from the blood transfer rate sensor 112.

The blood transfer rate calculation unit 246 calculates a blood transferrate according to a signal sent from the blood transfer rate parametersignal receiving unit 245. Specifically, it is possible to calculate ablood removal rate by multiplying a blood transfer speed (flow rateparameter), which is calculated from the blood transfer rate parametersignal, by a flow path area of the first blood transfer line 104.

First, the centrifugal pump control amount calculation unit 243calculates a target blood transfer rate, which is required tosynchronize the blood transfer rate of the centrifugal pump 220 with theblood removal rate, according to the blood removal rate received fromthe blood removal rate calculation unit 142. Subsequently, a correctedtarget blood transfer rate is calculated by correcting the target bloodtransfer rate according to the correction process data received from thecorrection process data receiving unit 151. The centrifugal pump controlamount calculation unit 243 increases or decreases a control amount(corrected rotational speed) to be output to the centrifugal pump 220 bycomparing the corrected target blood transfer rate to the blood transferrate received from the blood transfer rate calculation unit 246.

The synchronization of the blood transfer rate of the centrifugal pump220 with the blood removal rate is one aspect in which the bloodtransfer rate is controlled to be in a specific range (for example, in arange represented by a ratio to the blood removal rate, or in a rangerepresented by a difference in flow rate with respect to the bloodremoval rate) with respect to the blood removal rate.

In a case where the correction process is not performed, and there is nodeviation between the measurement characteristics, the centrifugal pump220 may be controlled via a rotational speed.

The correction process data receiving unit 151 receives the correctionprocess data and the correction process execution instruction, whichhave been set by the correction process setting unit 260, from thecorrection process setting unit 260.

The centrifugal pump control unit 244 outputs a signal, whichcorresponds to the rotational speed, to the centrifugal pump 220according to the control amount (corrected rotational speed) receivedfrom the centrifugal pump control amount calculation unit 243.

Hereinafter, an operational sequence in a case where the control unit240 of the artificial heart and lung apparatus 200 of the secondembodiment does not perform a correction process will be described withreference to FIG. 7. FIG. 7 is a flowchart showing the operationalsequence of the control unit 240 in a case where a correction process isnot performed in the artificial heart and lung apparatus 200.

(1) First, the control unit 240 receives a blood removal rate parametersignal (S31).

(2) Subsequently, the control unit 240 calculates a blood removal rateaccording to the received blood removal rate parameter signal (S32).

(3) Subsequently, the control unit 240 calculates a target bloodtransfer rate according to the blood removal rate calculated in S32(S33).

(4) Subsequently, the control unit 240 receives a blood transfer rateparameter signal (S34).

(5) Subsequently, the control unit 240 calculates a blood transfer rateaccording to the received blood transfer rate parameter signal (S35).

(6) Subsequently, the control unit 240 compares the target bloodtransfer rate calculated in S33 to the blood transfer rate calculated inS35, calculates (the target blood transfer rate—the blood transferrate), and determines whether the target blood transfer rate is greaterthan or equal to the blood transfer rate (S36).

If the target blood transfer rate is greater than or equal to the bloodtransfer rate (S36: Yes), the process proceeds to S37. If the targetblood transfer rate is less than the blood transfer rate (S36: No), theprocess proceeds to S38.

(7) The control unit 240 calculates a control amount (increasedrotational speed) for the centrifugal pump 220 according to a difference(=(the target blood transfer rate−the blood transfer rate)) calculatedin S36 (S37).

If the target blood transfer rate is equal to the blood transfer rate,the control amount (increased rotational speed) becomes zero.

(8) The control unit 240 calculates a control amount (decreasedrotational speed) for the centrifugal pump 220 according to a difference(=(the target blood transfer rate−the blood transfer rate)) calculatedin S36 (S38).

(9) Subsequently, the control unit 240 outputs a signal, whichcorresponds to the control amount calculated in S37 or S38, to thecentrifugal pump 220 (S39).

If S39 is executed, the process proceeds to S31.

S31 to S39 are repeatedly executed at predetermined intervals until asurgery is complete and blood circulation ends.

Hereinafter, an operational sequence in a case where the control unit240 of the artificial heart and lung apparatus 200 of the secondembodiment performs a correction process will be described withreference to FIG. 8. FIG. 8 is a flowchart showing the operationalsequence of the control unit 240 in a case where a correction process isperformed in the artificial heart and lung apparatus 200.

(1) First, the control unit 240 receives a blood removal rate parametersignal (S41).

(2) Subsequently, the control unit 240 calculates a blood removal rateaccording to the received blood removal rate parameter signal (S42).

(3) Subsequently, the control unit 240 calculates a target bloodtransfer rate according to the blood removal rate calculated in S42(S43).

(4) Subsequently, the control unit 240 receives correction process data(S44).

(5) Subsequently, the control unit 240 calculates a corrected targetblood transfer rate by correcting the target blood transfer rateaccording to the correction process data (S45).

(6) Subsequently, the control unit 240 receives a blood transfer rateparameter signal (S46).

(7) Subsequently, the control unit 240 calculates a blood transfer rateaccording to the received blood transfer rate parameter signal (S47).

(8) Subsequently, the control unit 240 compares the corrected targetblood transfer rate corrected in S45 to the blood transfer ratecalculated in S47, calculates (the corrected target blood transferrate—the blood transfer rate), and determines whether the correctedtarget blood transfer rate is greater than or equal to the bloodtransfer rate (S48).

If the corrected target blood transfer rate is greater than or equal tothe blood transfer rate (S48: Yes), the process proceeds to S49. If thecorrected target blood transfer rate is less than the blood transferrate (S48: No), the process proceeds to S50.

(9) The control unit 240 calculates a control amount (increasedrotational speed) for the centrifugal pump 220 according to a difference(=(the corrected target blood transfer rate−the blood transfer rate))calculated in S48 (S49).

If the corrected target blood transfer rate is equal to the bloodtransfer rate, the control amount (increased rotational speed) becomeszero.

(10) The control unit 240 calculates a control amount (decreasedrotational speed) for the centrifugal pump 220 according to a difference(=(the corrected target blood transfer rate−the blood transfer rate))calculated in S48 (S50).

(11) Subsequently, the control unit 240 outputs a signal, whichcorresponds to the control amount calculated in S49 or S50, to thecentrifugal pump 220 (S51).

If S51 is executed, the process proceeds to S41.

S41 to S51 are repeatedly executed at predetermined intervals until asurgery is complete and blood circulation ends.

Since the control unit 240 performs adjustment such that the flow rateof blood to be transferred to the first blood transfer line 104 issynchronized with the flow rate of removed blood flowing through theblood removal line 101, the artificial heart and lung apparatus 200 ofthe second embodiment is capable of transferring the same amount ofblood as the amount of removed blood to the patient P.

As a result, even if the blood removal rate changes, it is possible toensure a suitable blood transfer rate corresponding to the blood removalrate, and to perform suitable blood circulation.

In the artificial heart and lung apparatus 200 of the second embodiment,the correction process setting unit 260 is provided, and the controlunit 240 corrects a deviation between the measurement characteristics ofthe blood removal rate sensor 111 and the blood transfer rate sensor 112according to correction process data input to the correction processsetting unit 260. As a result, it is possible to efficiently synchronizethe blood transfer rate of the centrifugal pump 220 with the bloodremoval rate.

In the artificial heart and lung apparatus 200 of the second embodiment,the centrifugal pump 220 is used as a blood transfer pump, and thus, itis possible to promptly transfer blood at a stable blood transfer rate.

In the artificial heart and lung apparatus 200 of the second embodiment,the blood removal regulator 121 is provided in the blood removal line101, and thus, the blood removal rate is suitably adjusted.

The blood transfer regulator 122 is provided in the first blood transferline 104, and is capable of preventing the back flowing of blood byblocking the first blood transfer line 104 when the centrifugal pump 220stops.

The present invention is not limited to the embodiments, and changes canbe made to the embodiments in various forms insofar as the changes donot depart from the concept of the invention.

In the artificial heart and lung apparatuses 100 and 200 of theembodiments, the blood transfer rate is synchronized with the bloodremoval rate. Alternatively, the blood transfer rate may be adjusted tobe in a specific range with respect to the blood removal rate.

In the embodiments, the artificial heart and lung apparatuses 100 and200 respectively include the correction process setting units 160 and260. Alternatively, setting as to whether the correction process settingunits 160 and 260 are included may be arbitrarily performed.

In a case where the correction process setting units 160 and 260 areincluded, the correction process setting units 160 and 260 may beexternally attachably included.

In the embodiments, the blood removal rate sensor 111 and the bloodtransfer rate sensor 112 which measure the flow speed of blood arerespectively used as blood removal rate measurement means and bloodtransfer rate measurement means. Alternatively, a blood removal rate anda blood transfer rate may be measured by measuring a blood removal rateparameter (including a blood removal rate) other than a blood removalspeed and a blood transfer rate parameter (including a blood transferrate) other than a blood transfer speed.

In the embodiments, ultrasonic sensors are used as the blood removalrate sensor 111 and the blood transfer rate sensor 112. Alternatively,various well-known flow rate measurement means using laser, infraredlight, or the like may be used instead of an ultrasonic sensor.

In the embodiments, the roller pump 120 and the centrifugal pump 220 areused as blood transfer pumps. Alternatively, other types of bloodtransfer pumps may be used.

In the first embodiment, flow rate adjustment means is not provided inthe blood transfer line. Alternatively, flow rate sensors (flow rateparameter measurement means) such as ultrasonic sensors may be suitablyprovided in the first blood transfer line 104 and the second bloodtransfer line 106.

In the first embodiment, the blood removal regulator 121 is provided asflow rate adjustment means, and in the second embodiment, the bloodremoval regulator 121 and the blood transfer regulator 122 are providedas flow rate adjustment means. Alternatively, in the first and secondembodiments, neither the blood removal regulator 121 nor the bloodtransfer regulator 122 may be provided. In a case where flow rateadjustment means is provided, setting as to whether either or both ofthe blood removal regulator 121 and the blood transfer regulator 122 areprovided may be suitably performed, and portions of a blood removal lineand a blood transfer line, in which the blood removal regulator 121 andthe blood transfer regulator 122 are provided, may be suitably set.

Flow rate measurement means other than the blood removal regulator 121and the blood transfer regulator 122 may be provided.

In the first and second embodiments, the blood removal regulator 121 andthe blood removal rate sensor 111 are disposed in the blood removal line101 in the listed sequence. Alternatively, the blood removal rate sensor111 and the blood removal regulator 121 are disposed in the listedsequence.

In the second embodiment, the blood transfer regulator 122 and the bloodtransfer rate sensor 112 are disposed in the first blood transfer line104 in the listed sequence. Alternatively, the blood transfer regulator122 and the blood transfer rate sensor 112 may be disposed in the secondblood transfer line 106 instead of the first blood transfer line 104.The blood transfer rate sensor 112 and the blood transfer regulator 122may be disposed in the listed sequence.

In the embodiments, FIGS. 3, 4, 7, and 8 show examples of the flowchartsshowing schematic steps of controlling the roller pump 120 and thecentrifugal pump 220 of the present invention. Alternatively, controlmay be performed via methods (algorithms) other than the methods shownin the flowcharts.

In the embodiments, a blood circulation system is applied to theartificial heart and lung apparatuses 100 and 200. Alternatively, thepresent invention may be applied to an auxiliary circulation apparatus(blood circulation system) and the like, which does not include areservoir and is used in a cardiac surgery operation, other than anartificial heart and lung apparatus.

INDUSTRIAL APPLICABILITY

In a case where a blood circulation system of the present inventioncirculates removed blood via a blood transfer pump, the bloodcirculation system is capable of stably transferring blood at a suitableflow rate.

REFERENCE SIGNS LIST

P: PATIENT (HUMAN BODY)

100, 200: ARTIFICIAL HEART AND LUNG APPARATUS (BLOOD CIRCULATION SYSTEM)

101: BLOOD REMOVAL LINE

102: RESERVOIR

104: FIRST BLOOD TRANSFER LINE (BLOOD TRANSFER LINE)

105: ARTIFICIAL LUNG

106: SECOND BLOOD TRANSFER LINE (BLOOD TRANSFER LINE)

111: BLOOD REMOVAL RATE SENSOR (BLOOD REMOVAL RATE MEASUREMENT MEANS)

112: BLOOD TRANSFER RATE SENSOR (BLOOD TRANSFER RATE MEASUREMENT MEANS)

120: ROLLER PUMP (BLOOD TRANSFER PUMP)

121: BLOOD REMOVAL REGULATOR (FLOW RATE ADJUSTMENT MEANS)

122: BLOOD TRANSFER REGULATOR (FLOW RATE ADJUSTMENT MEANS)

140, 240: CONTROL UNIT

160, 260: CORRECTION PROCESS SETTING UNIT

220: CENTRIFUGAL PUMP (BLOOD TRANSFER PUMP)

What is claimed is:
 1. A blood circulation system that can be connectedto a human body, the system comprising: a blood transfer pump; a bloodremoval line through which blood removed from the human body flows tothe blood transfer pump; a blood transfer line that transfers blood,which is sent from the blood transfer pump, to the human body; a bloodremoval rate measurement means that is provided in the blood removalline to measure a blood removal rate parameter of blood flowing throughthe blood removal line; a blood transfer rate measurement means that isprovided in the blood transfer line to measure a blood transfer rateparameter of blood flowing through the blood transfer line; and acontrol unit, wherein the control unit is programmed to control a bloodtransfer rate of the blood transfer pump by controlling a rotation speedof the blood transfer pump with a control signal, such that a transferrate calculated from the blood transfer rate parameter is synchronizedwith a removal rate calculated from the blood removal rate parameter. 2.The blood circulation system according to claim 1, further comprising: acorrection process setting unit, wherein according to correction processdata input to the correction process setting unit, the control unitperforms correction such that the blood transfer rate of the bloodtransfer pump corresponds to the blood removal rate.
 3. The bloodcirculation system according to claim 1, further comprising: acentrifugal pump that is the blood transfer pump, wherein the controlunit controls the rotational speed of the centrifugal pump.
 4. The bloodcirculation system according to claim 1, wherein flow rate adjustmentmeans is provided in the blood removal line.
 5. The blood circulationsystem according to claim 1, wherein flow rate adjustment means isprovided in both the blood removal line and the blood transfer line. 6.A blood circulation method using a blood circulation system that can beconnected to a human body, the blood circulation system comprising: ablood transfer pump; a blood removal line through which blood removedfrom the human body flows to the blood transfer pump; and a bloodtransfer line that transfers blood, which is sent from the bloodtransfer pump, to the human body, the blood circulation methodcomprising: measuring a blood removal rate parameter of blood flowingthrough the blood removal line; measuring a blood transfer rateparameter of blood flowing through the blood transfer line; calculatinga removal rate from the blood removal rate parameter; calculating atransfer rate from the blood transfer rate parameter; and controlling ablood transfer rate of the blood transfer pump by controlling arotational speed of the blood transfer pump, such that the transfer rateis synchronized with the removal rate.